(a) Field of the Invention
The present invention relates to a method and apparatus for measuring a user's location. More particularly, the present invention relates to an integrated positioning method and apparatus which measure a user's location by integrating positioning results obtained through different positioning schemes.
(b) Description of the Related Art
In recent years, personal handheld terminals capable of providing position information have been spreading rapidly. Moreover, services for providing position information and geographical information via portable terminals are growing rapidly. At present, positioning services used to provide position information include a GNSS (Global Navigation Satellite System) service using a navigation satellite system such as the GPS (Global Positioning System) and a WPS (WiFi Positioning System) service using WiFi APs (access points).
The GNSS service is one of the most popular positioning services today, and provides relatively high reliability and high accuracy in an environment such as an open area where navigation signals are properly received from navigation satellites in orbit. However, due to the characteristics of the GNSS service, GNSS signals may not be received properly or may not be received at all in environments such as in indoor areas, underground areas, or alleys between buildings. Due to this, the GNSS service is poor in positioning quality or the service itself is limited. That is, in urban areas to which the GNSS service is mainly targeted, the closer a user is to a building, the more severe effects signal diffraction, reflection, blocking, etc. have. Thus, positioning errors increase and positioning reliability decreases with this increase. This is the biggest disadvantage of the GNSS service.
The WPS service is a method of estimating location using APs in a WLAN (wireless local area network). In the WPS service, usually, a positioning terminal measures the strengths of signals received from APs and calculates signal transmission distances according to signal attenuation. Then, the positioning terminal estimates location using the calculated values. Alternatively, the positioning terminal estimates location using a list of APs found at a point of measurement, based on proximity positioning.
The WPS service is efficient in urban areas or indoor areas where APs are densely deployed. However, the WPS service provides low reliability in outdoor or suburban areas where APs are sparsely deployed (i.e., environments where positioning resources are relatively sparse), and exhibits wide differences in performance even in the same area depending on the distribution characteristics of APs.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.